IBX-7947: Help messages configuration corrected

[julitafalcondusza]

Question	Answer
JIRA Ticket	(https://github.com/ibexa/fieldtype-page/pull/120)
Versions	4.6+

Help messages configuration corrected:

• Help messages for form fields
• Help message in nested attributes

Checklist

• [x] Text renders correctly
• [x] Text has been checked with vale
• [x] Description metadata is up to date
• [x] Redirects cover removed/moved pages
• [x] Code samples are working